Electric extension cord plug



Jan. 10, 1950 A. c. HAss 2,493,871

ELECTRIC EXTENSION CORD PLUG Filed Dec. 1948 2 Sheets-Sheet 1 INVENTOR. Wad 616501; 40 E BY A 7' TOR/VEVJ Jan. W, 195% A. c. l-mss 2, ,871

ELECTRIC EXTENSION CORD PLUG Filed Dec. z 394% 2 Sheets-Sheet 2 1N VEN TOR.

Patented Jan. 10, 1950 UNITED ES P TENT-Car i 2,493,871

ELECTRIC EXTENSION CORD PLUG I Albert C. Hass, lilmhurst, Ill. Application December 23,1948, Serial No. 66,925

, screw-threaded shell therein.

It is among the objects of the invention to provide an improved electric extension cord plug which may be inserted, without turning, into a conventional screw socket having a screwthreaded, cylindrical shell, and firmly engaged in said socket against accidental removal, which makes an effective electrically conductive contact with the socket shell and is strong and durable in construction, economical to manufacture, neat and attractive in appearance, and easy to use.

Other objects and advantages will become apparent from a consideration of the following description and the appended claims in conjunction with the accompanying drawings, wherein:

Figure 1 is a longitudinal elevation of an ex-- Figure 3 is a longitudinal, medial cross-section through the improved plug taken in a plane substantially parallel to the plane of the paper with the plug in the position illustrated in Figure 2;

Figure 4 is a transverse cross-section taken substantially on the line 4-4 of Figure 1;

Figure 5 is a longitudinal elevation of the upper-half portion of the plug as illustratedin Figure 4;

Figure 6 is a longitudinal elevation of the lowerhalf portion of the plug as illustrated in Figure 4, portions being broken away and shown in crosssection to better illustrate the construction of the plug;

Figure 7 is a view similar to Figure 5 of a fragmentary lower portion of the plug'showing the 5 parts in a difierent operative position from that illustrated in Figure 5;

Figure 8 is a perspective view of an encircling band for the portion of the plug received in the screw socket;

Figure 9 is a perspective view of a dog for releasably locking the plug in the socket;

Figure 10 is a perspective view of a contact spring constituting an operative component of the plug; and

mins, (c1; 173-360) improvements in Figure 11 is a perspective view of a split spring .ring which retains the two portions of the plu With continued reference to the drawings, the conventional screw socket, generally indicated at H), has an outer, cylindrical shell l| conventionally formed of thin metal, such as brass, although it may be formed of ceramics or other suitable material, a body l2 of insulating material in the outer shell carrying a center contact {3,

an inner cup or shell [4 formed of electrically conductive material, such as thin, rolled brass,

and provided with screw threads l5, and an insulating shell or cylinder l6 interposed between the outer shell and the inner shell ll. The line or power wires are-connected respectively to the center contact [3 and the inner shell I! of the screw socket. Such asocket is conventionally used to receive a lamp bulb, but, when provided with a suitable plug, may be used for other purposes, such as for supplying electric current to a table lamp. or floor lamp, an electric iron, toaster, or other appliance. The extension cord socket has an elongated shell, generally indicated at 11, of electrically insulative material, such as, hard rubber or synthetic resin plastic, and is longitudinally divided into two substantially similar parts or halves l8 and I9, as clearly illustrated in Figures 2, 4,5, and 6. The shell I! is hollow and of circularcrosssection and includes a,reduced cylindrical portion 20 receivable in the inner shell I4- of the screw socket, and having a diameter considerably :outer end wall 24 of the large portion 2| to a loca- ,tion within the step portion22 and spaced from the reduced portion 20. The reduced portion 20 is provided in its cylindrical wall with a pair of diametrically-opposed slots 25 which communicate with theinterior concavity of the shell and is also provided with an end wall 26 secured to or formed integrall with the part l9 and underlying the smaller end of the part l8 of the shell.

, The reduced portion 20 of the shell is annularly recessed and a circular metal band 26 sur- 1 roundsthe reducedportion of the shell within,

this recess and is provided with slots 21 registering with the slots 25 in the reduced end portion of 'the shell. The large portion 2| of the shell is also provided with an annular groove 28 and a split, spring ring 29 is disposed in the groove 28 surrounding the large portion of the shell. This spring ring is provided at'its ends with inwardlydirected tongues 30 receivable in a notch provided in the shell withinflthemgroovelzfl, so thatthe ring firmly locks the two; parts l8 meantime-15mm 10;;ahes'ockeuciit1 together when operatively disposed in' the groove 5 rated ends of the dogs, the two links 48 are brought to exposition of relative alignment, as illustrated in Figure '7, so that the dogs are releasably locked in engagement with the socket ,inner shell and the plug cannot be removed from he hanid e542} is: ;in'a'nual1y pulled outwardly ofthe' plughell. When itis desired to remove the plug from the socket, the handle ""12 is pulled outwardly, retracting theserrated Hands I46 ;-ofithe;-i1iogs, whereupon the plug is easily A center contact 3| is secured in the end wall 26 for contact with the center icontactilii'uofith'e-5 socket, and a pair of binding posts 32 and 33lare movableout of the socket.

secured in the cavity of the plug within'the part 19. A conductor 34 connectsjathescemerscontact 3| with the binding post 32-which is also con nected with one wire 35, of the extension 'cord 361' Thein'vention may be embodied in other speclflcsformsewithout departing from the spirit or essential characteristicslthereof. The present embodiment is, therefore, to be considered in all The other wire 3'l of the extension cord is con- 20 respects as illustrative and not restrictive, the

:nected' with 'the bindingm os'ti 33and 'the two 'i-wvires 35 and 31 areitied 'together in an Underwriters knot 38 within the -ca',vity 'in thepart I? to aire-vent "the cord fr-om pulling out through the mole- 39 provided in the part I 9 'f0r the reception 25 A'- 'conta'ct leaf springfl'll is secure'd in the part l 9 andis electrically connectedto thebinding post 33." 'This. leaf spring extends longitudinally of the scopeof the inventionibeingiindicated: by the-ap pended claims r-rather thanby the foregoing deascriptiongand all changes which comewithin the imeahing and ran'ge o'f'equivalency of the claims are, therefore, intended to be embraced therein. i Wh at is claimed-is:

-1. An electric extension 'cord plug comprising -=-a=hollowg: elongated shell of 'electrically insul-ative material longitudinally split' 'into twosubs'tans plug and-is positioned-'contiguous'to'the open side tially'similar parts andv611d a rof the space' 'between' the two guide ribs 23, when the -two-:parts' of the' plug are -operatively assembled. A-plungei ll preferably of square -or-'rectangular cross-sectiorial- '-='sh'ape, is Fslidably 'duced cylindricaliportion receivable in a conven Ftional screwsocket 1 :an'dprovided with an end wallpsaid shell having a pai'ro'f guide ribs" there- :in :spaced from-said r'educ'e'd portion and a pair or mounted=-betWeen the tw0 guideribs 23, and 'in'es pposed, longitudinallwext ndin sl ts n-t vfrictional=fengagement with the spring lfl. This l plunger is o'f 'electrically conductive material, and

1a hafidlefl-of=electrically insulative "material -is secured to one end 'oi this plunger "by 'a *stem' fl "whiche xten lBf-"b'f the plu'g' shell.

-'A pair-of-socket-engaging dogs are mounted in the reduced and step 'poi'tions of the sh'ellgand have serrated end p'ortions-"d'fi' projectible"through -lindrical wall of said- "reduced portion, a center -trmina1= extending through- 'said end :wall, a pair :of spa'ced-apart binding.=.posts for the wire-lends of an eXtension cord,said ding-postsbeing dissh'ell ine'ar theend of the latter opposite said r'educe'd portion,ameans elect'ric ally tcon-ne'ctingls'aid center terminalto one of said iblfldil'lg p'osts, L a leaf spring connected .to "one :of'saidloinding posts and extending longitudinally D GtiVeQSIOtS M in the reducedl portion' of the"'45 of said oshell: contiguous-to saidguideribs a "shell an'd -through'respective slots 27 "in theband 26 to engage in the-threads l fi i'n theinner-shell I 4' bf' the socket; as clearly illustrated in Figure 1.- A" piVot -pin M"extends' transversely vzplurrger fof ele'c trically conductive materialf slidi'ableibetween 'said guide ribs -in contact with said irspring," aihandleiiof electr ically insulative'-m'aterial secured to one end of "id' plunger-and ex "through' the reduced -porti'on -of the shell adjacent BO ftendingvout: offithefiend bf aid shelpo said the step portion n *an(:Fth'roiigh-w gis'tering 'aper *turesin the twodogs 4 5 pivo'tally; connect the =d0gs-to ea 'eh*other and'to -th'e-shll, the two dogs be"in g*crossed over atthe pivofipo-int;-=as isclearly illustratedin Figures 5 a-nd-7. j

-'A pair of li'riks 48- are 'each pivotally connected at one end"-to the endot *the i plunger 41 opposite the end of the plunger to which the h-an'clle ET-is "attachedfiby' a common pivot pin wf ai'ld are 1 'edu'ced:1portion,@a pair ot' socketerrg'aging dogs iioftelectricall-y conductive' m aterial in said-shell thawing: serrated er-id port ons projectiblelthrough --r:espective!sl'ots said ell e'du'ced :portion to 3:55 engage sock 'et screw threajds whensaid reduced portionzis inserted intoia screw socket, a pivotpin :qtivotally iconnectin'g said dogs---together and V1110 said shell, a pair of links of electrically conduc- -tive naterlial each'pivotallyiconnected at one'end "adjacent ends-*ofrespective dojg'sf4'5 by respective '"Divot-pins' 50. J 7 'J With ithe parts' inope'rative assembly-gas lustrated in -Figures *1 and 2;:when the handle' lz is mulled-outwardly of the' scicket shll fifithe' two w envoy -a 48 are lm-ought to the angularly-tlispos'ed; "relativeposition illustrated -"in Figure 5, and ithe "serrated ends 6 of the two dogsiMeme-retracted through"the corres-poriding'slots2-5 in the re'duced,

rounding the! reduced erusao'f sa'idshell; and ea split spi ing ring surrouiidihg sai'd s-heH at a location'*space'd'ifrom said=red1icedaportion'to hold cylindricalend portion bf the pmgsnen: -Thef W the two parts of said shell in operative-assembly.

reduc'edportion of the plug inay 'ow be inserted into a -screw-' soekt, 'su'ch as' ilIuStra-ted in "Figure *1. M-ter' the reduced portionof the plug isdisposed' withiri th sner ensu esthe screw 2. Ane1ectric egtensiomcorea p'lug comprising an elongateihollovv shHqoi'ig itlidlriaHy split-into *two -substar it my s ii'nil'ar parts', said sliell -hav- -ingat one end a redused eylindrical portion rre- -op'erati-ve position to releasalblypositely-disposed slots in its cylindrical wall, a pair of dogs of electrically conductive material pivotally mounted in said shell and having serrated end portions projectible through respective slots in said reduced portion to engage the inner surface of a screw socket receiving said reduced portion of said plug, a plunger slidable in said plug shell, means pivotally inter-connecting the adjacent ends of said plunger and said dogs for pivotal movement of said dogs upon longitudinal movement of said plunger in said shell, a nandle secured to the end of said plunger opposite the dog-connected end of the latter and extending through the end of said shell opposite said reduced shell portion, an end wall on said reduced portion, a center contact carried by said end wall, a pair of binding posts in said plug shell receiving respective wires of an extension cord, and means in said shell electrically connecting said center contact and said plunger to respective binding posts, said means pivotally interconnecting said handle and said dogs comprising a pair of links each pivotally connected at one end to said handle :at one end of the latter and pivotally connected at their opposite ends to said dogs respectively, said links having a longitudinally aligned operative position in which they lock said dogs in projected position.

ALBERT C. HASS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,206,245 Powell Nov. 28, 1916 1,317,548 Casper Sept. 30, 1919 1,484,492 Hansbrough Feb. 19, 1924 2,439,462 Frank Apr. 13, 1948 

